Abstract A rate-independent, de-cohesive damage model for the fracture modelling of large, cellular, plate-like, quasi-brittle structures is proposed. A hybrid, three-dimensional finite-discrete element method to investigate sea ice sheet fracture is then introduced, followed by three applications. The uniaxial tensile fracture of an ice sheet of varying physical sizes is examined first. The effects of both the size of an ice sheet and the loading rate applied on the effective tensile strength are investigated. The vertical penetration fracture of an ice sheet loaded by a rigid, flat-ended, cylindrical indenter is examined next. The breakthrough loads and strengths of an ice sheet of varying physical sizes are computed, applicable scaling rules as regards to the vertical breakthrough strength searched for. To conclude, the breaking of an ice sheet containing a circular hole by a surfacing, rigid, truncated cone is studied (an axisymmetric contact problem). The loads on the cone are computed and then compared with loads that can be obtained analytically for a case in which a structure is stationary, a sheet moves, and the contact is unilateral. While computing the tensile and the breakthrough strengths, a set of self-similar sheet samples with an in-plane size range of 1:16 is examined. The samples are square; have a side length of either L = 10 , 20, 40, 80, or 160 m; and a thickness of either h = 0.5 , 1.0, or 1.5 m. With the sheets containing holes, only the largest samples ( L = 160 m) are investigated. The results indicate that i ) both the tensile and the breakthrough strengths are strong functions of both L and h ; ii ) the tensile strength is a strong function of the applied loading rate; iii ) the failure mode as regards to the vertical penetration fracture changes drastically as a function of L ; iv ) the model is able to demonstrate both radial and circumferential cracking; and that v ) the proposed (in-direct) approach to compute ice loads on a conical offshore structure provides realistic results.

中文翻译：

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海冰盖断裂的有限离散元建模

摘要 提出了一种用于大型、蜂窝状、板状、准脆性结构断裂建模的与速率无关的脱粘损伤模型。然后介绍了一种用于研究海冰盖断裂的混合三维有限离散元方法，然后进行了三个应用。首先检查不同物理尺寸的冰盖的单轴拉伸断裂。研究了冰盖大小和加载速率对有效拉伸强度的影响。接下来检查由刚性、平端、圆柱形压头加载的冰盖的垂直穿透断裂。计算了不同物理尺寸的冰盖的突破载荷和强度，适用于搜索的垂直突破强度的缩放规则。总结一下，研究了通过曲面的刚性截锥破坏包含圆孔的冰盖（轴对称接触问题）。计算锥体上的载荷，然后与结构静止、片材移动和单边接触的情况下可以通过解析获得的载荷进行比较。在计算拉伸强度和突破强度时，检查了一组平面内尺寸范围为 1:16 的自相似片材样品。样品是方形的；边长为 L = 10、20、40、80 或 160 m；厚度为 h = 0.5、1.0 或 1.5 m。对于含有孔的板材，仅研究最大的样品 (L = 160 m)。结果表明： i) 拉伸强度和突破强度都是 L 和 h 的强函数；ii) 抗拉强度是施加的加载速率的强函数；iii) 垂直穿透断裂的失效模式作为 L 的函数急剧变化；iv ) 该模型能够证明径向和周向开裂；并且 v ) 提议的（间接）计算锥形海上结构上的冰载荷的方法提供了现实的结果。